Zookeeper 创建6种的节点实例(转)

原文:https://blog.csdn.net/pengweismile/article/details/115444734

作者:伟娃娃

Zookeeper是Apache Hadoop的一个子项目,它主要用来解决分布式系统中经常遇到的一些数据管理问题,例如,统一命名,状态同步,集群管理,分布式应用配置管理。

Zookeeper的定位,这个动物园的管理者,如下图

ookeeper又2个特性
特性一 树形结构,每个子目录可以被增加删除

特性二 事件监听机制

特性一
zookeeper可以对目录树中的任意一个节点进行监听。监听是只监听目录下面的目录变化。

zookeeper类似一个文件系统,每个子目录被称为目录节点,允许我们自由的增加删除目录节点。

 

znode节点的类型:

持久化目录节点(PERSISTENT), 创建好之后就永久存在
持久化顺序编号节点(PERSISTENT_SEQUENTIAL),创建好节点后还可以默认带个自增的编号
临时目录节点(EPHEMERAL),和sessionId绑定的,当客户端被关闭之后,对于的临时目录节点会被删除
历史顺序编号目录节点(EPHEMERAL_SEQUENTIAL),临时节点带个自增的编号
容器节点(Container),3.5.3新增的特性,没有子节点的容器节点会被清除掉。
TTL节点,3.5.3新增的特性,位节点设定了失效时间。具体失效时间却决于后台检测失效线程的轮询频率。
临时节点被删除过程:

 

长连接和短连接的区别,根据自己的业务来定的。

Zookeeper的安装

Step1:配置JAVA环境,检验环境:

java ‐version

Step2: 下载解压 zookeeper

wget https://mirror.bit.edu.cn/apache/zookeeper/zookeeper‐3.5.8/apache‐zookeeper‐3.5.8‐bin.tar.gz

https://zookeeper.apache.org/releases.html#download

tar ‐zxvf apache‐zookeeper‐3.5.8‐bin.tar.gz
 
cd apache‐zookeeper‐3.5.8‐bin

Step5: 检测是否启动成功

ps -ef| grep zookeeper

Step6: 连接服务器

bin/zkCli.sh ‐server ip:port

创建不同的节点

-s: 顺序节点-

e: 临时节点

-c: 容器节点

-t: 可以给节点添加过期时间,默认禁用,需要通过系统参数启用

zoomkeeper在目录上的增删改查

[zk: localhost:2181(CONNECTED) 4] create /test "hello"
Created /test
[zk: localhost:2181(CONNECTED) 5] get /test
hello
[zk: localhost:2181(CONNECTED) 6] set /test "hello world"
[zk: localhost:2181(CONNECTED) 7] get /test
hello world
[zk: localhost:2181(CONNECTED) 8] delete /test
[zk: localhost:2181(CONNECTED) 9] get /test
org.apache.zookeeper.KeeperException$NoNodeException: KeeperErrorCode = NoNode for /test
[zk: localhost:2181(CONNECTED) 10] 

ZK中没有相对路径一说, 所有路径都是绝对路径。

创建子目录,操作

[zk: localhost:2181(CONNECTED) 10] create /test1/sub1 hello
Node does not exist: /test1/sub1
[zk: localhost:2181(CONNECTED) 11] create /test1 hello1
Created /test1
[zk: localhost:2181(CONNECTED) 12] create /test1/sub1 "hello sub"
Created /test1/sub1
[zk: localhost:2181(CONNECTED) 13] ls -R /test1
/test1
/test1/sub1

创建顺序节点 -s

 
[zk: localhost:2181(CONNECTED) 22] create /seq
Created /seq
[zk: localhost:2181(CONNECTED) 24] create -s /seq/Allen- "hello"
Created /seq/Allen-0000000001
[zk: localhost:2181(CONNECTED) 25] create -s /seq/Allen- "hello"
Created /seq/Allen-0000000002
[zk: localhost:2181(CONNECTED) 26] create -s /seq/Allen- "hello"
Created /seq/Allen-0000000003
[zk: localhost:2181(CONNECTED) 27] create -s /seq/Allen- "hello"
Created /seq/Allen-0000000004
[zk: localhost:2181(CONNECTED) 28] create -s /seq/Allen- "hello"
Created /seq/Allen-0000000005
[zk: localhost:2181(CONNECTED) 30] ls -R /seq
/seq
/seq/Allen-0000000001
/seq/Allen-0000000002
/seq/Allen-0000000003
/seq/Allen-0000000004
/seq/Allen-0000000005
[zk: localhost:2181(CONNECTED) 31] 

创建临时节点 -e:

[zk: localhost:2181(CONNECTED) 31] create -e /ephemeral "hello ephemeral"
Created /ephemeral
[zk: localhost:2181(CONNECTED) 32] get -s /ephemeral
hello ephemeral
cZxid = 0x15
ctime = Mon Apr 05 03:57:30 PDT 2021
mZxid = 0x15
mtime = Mon Apr 05 03:57:30 PDT 2021
pZxid = 0x15
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x1001f373c3a0001
dataLength = 15
numChildren = 0

临时节点与持久节点的区别在于上面节点元数据信息的ephemeraOwner的值是不一样的。当客户端关掉,临时节点就没有了。临时节点下面是不能有子节点的。

[zk: localhost:2181(CONNECTED) 34] create -e /ephemeral/sub
Ephemerals cannot have children: /ephemeral/sub
[zk: localhost:2181(CONNECTED) 35] 

 

[zk: localhost:2181(CONNECTED) 33] get -s /seq
null
cZxid = 0xe
ctime = Mon Apr 05 03:54:16 PDT 2021
mZxid = 0xe
mtime = Mon Apr 05 03:54:16 PDT 2021
pZxid = 0x14
cversion = 6
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 0
numChildren = 6
[zk: localhost:2181(CONNECTED) 34] 

创建临时顺序节点 -e -s

[zk: localhost:2181(CONNECTED) 37] create -e -s /seq-eph
Created /seq-eph0000000005
[zk: localhost:2181(CONNECTED) 38] create -e -s /seq-eph
Created /seq-eph0000000006
[zk: localhost:2181(CONNECTED) 39] create -e -s /seq-eph

创建container节点 -c, 唯一的区别是,当删除掉container节点下的所有子节点后, container节点本身也会被清除掉

[zk: localhost:2181(CONNECTED) 3] create -c /container
Created /container
[zk: localhost:2181(CONNECTED) 4] create /container/sub1
Created /container/sub1
[zk: localhost:2181(CONNECTED) 5] create /container/sub2
Created /container/sub2
[zk: localhost:2181(CONNECTED) 6] create /container/sub3
Created /container/sub3
[zk: localhost:2181(CONNECTED) 7] ls -R /container
/container
/container/sub1
/container/sub2
/container/sub3
[zk: localhost:2181(CONNECTED) 8] delete /container/sub1
[zk: localhost:2181(CONNECTED) 9] delete /container/sub2
[zk: localhost:2181(CONNECTED) 10] delete /container/sub3
[zk: localhost:2181(CONNECTED) 11] ls /
[container, seq, seq0000000002, test1, zookeeper]
[zk: localhost:2181(CONNECTED) 12] ls /
[container, seq, seq0000000002, test1, zookeeper]
[zk: localhost:2181(CONNECTED) 16] ls /
[seq, seq0000000002, test1, zookeeper]

创建就ttl节点 -t ,ttl节点的特性是可以创建一个打失效时间的节点,失效时间过来之后节点会被自动删除。

1. 关闭服务

[allen@localhost bin]$ ./zkServer.sh stop ../zoo.cfg 
/usr/bin/java
ZooKeeper JMX enabled by default
Using config: ../zoo.cfg
Stopping zookeeper ... ./zkServer.sh: line 213: kill: (61723) - No such process
STOPPED
[allen@localhost bin]$ 

2. 添加扩展的业务,在zkServer.sh 中增加如下配置

-Dzookeeper.extendedTypesEnabled=true

 3. 重新启动服务

[allen@localhost bin]$ ./zkServer.sh start ../zoo.cfg 
/usr/bin/java
ZooKeeper JMX enabled by default
Using config: ../zoo.cfg
Starting zookeeper ... STARTED
[allen@localhost bin]$ vi zkServer.sh 
[allen@localhost bin]$ ./zkCli.sh
/usr/bin/java
Connecting to localhost:2181

如下, ttl-note在一段时间后自己就没有了,不用手动删除。

[zk: localhost:2181(CONNECTED) 0] create -t 5000 /ttl-node ttttt
Created /ttl-node
[zk: localhost:2181(CONNECTED) 1] ls /
[seq, seq0000000002, test1, ttl-node, zookeeper]
[zk: localhost:2181(CONNECTED) 2] ls /
[seq, seq0000000002, test1, ttl-node, zookeeper]
[zk: localhost:2181(CONNECTED) 9] ls /
[seq, seq0000000002, test1, ttl-node, zookeeper]
[zk: localhost:2181(CONNECTED) 10] ls /
[seq, seq0000000002, test1, zookeeper]
[zk: localhost:2181(CONNECTED) 11] 

 

posted @ 2023-10-24 13:40  奋斗终生  Views(274)  Comments(0Edit  收藏  举报